KR102715511B1 - Transmitter, receiver and data processing method - Google Patents

Abstract

The present technology relates to a transmitting device, a receiving device, and a data processing method that enable band control of PLPs when one frequency band is configured with a plurality of PLPs. The transmitting device determines the number of cells of components transmitted by each PLP so that the total number of cells of a physical layer frame including a plurality of PLPs matches the sum of the number of cells of the plurality of PLPs, and transmits a broadcast stream including the physical layer frame. The present technology can be applied to, for example, a system that transmits a broadcast stream including a physical layer frame including a plurality of PLPs.

Description

Transmitter, receiver and data processing method

The present technology relates to a transmitter, a receiver and a data processing method, and more particularly, to a transmitter, a receiver and a data processing method that enable band control of a PLP when one frequency band is configured with a plurality of PLPs.

In ATSC (Advanced Television Systems Committee) 3.0, one of the next-generation terrestrial broadcasting standards, it has been decided that the method of using IP (Internet Protocol) packets containing UDP (User Datagram Protocol) packets (hereinafter referred to as the IP transmission method) rather than TS (Transport Stream) packets will be adopted primarily for data transmission. In addition, it is expected that IP transmission method will be adopted in broadcasting standards other than ATSC 3.0 in the future.

Here, transmission data such as content can be transmitted in PLP (Physical Layer Pipe) units (see, for example, Non-patent Document 1). In addition, in ATSC3.0, one frequency band (for example, a 6㎒ frequency band corresponding to one channel (physical channel)) is configured by one or more PLPs (Physical Layer Pipes).

ETSI EN 302 755 V1.2.1(2010-10)

However, a technical method for configuring one frequency band with multiple PLPs has not been established, and a proposal for performing band control of PLPs in cases where one frequency band is configured with multiple PLPs is requested.

This technology was developed in consideration of such a situation, and enables band control of PLPs when one frequency band is composed of multiple PLPs.

A transmitting device of a first aspect of the present technology is a transmitting device comprising a processing unit that determines the number of cells of a component transmitted by each PLP such that the total number of cells of a physical layer frame including a plurality of PLPs (Physical Layer Pipes) matches the total number of cells of the plurality of PLPs, and a transmitting unit that transmits a broadcast stream including the physical layer frame.

The transmitting device of the first aspect of the present technology may be an independent device or an internal block constituting a single device. In addition, the data processing method of the first aspect of the present technology is a data processing method corresponding to the transmitting device of the first aspect of the present technology described above.

In the transmitting device and data processing method of the first aspect of the present technology, the number of cells of a component transmitted by each PLP is determined so that the total number of cells of a physical layer frame including a plurality of PLPs matches the sum total of the number of cells of the plurality of PLPs, and a broadcast stream including the physical layer frame is transmitted.

A receiving device of a second aspect of the present technology is a receiving device having a receiving unit for receiving a broadcast stream including a physical layer frame including a plurality of PLPs, the physical layer frame having the number of cells of components transmitted by each PLP allocated such that the total number of cells of the physical layer frame matches the total number of cells of the plurality of PLPs, and a processing unit for processing the physical layer frame.

The receiving device of the second aspect of the present technology may be an independent device or an internal block constituting a single device. In addition, the data processing method of the second aspect of the present technology is a data processing method corresponding to the receiving device of the second aspect of the present technology described above.

In a receiving device and a data processing method of the second aspect of the present technology, a broadcast stream including a physical layer frame including a plurality of PLPs, wherein the number of cells of a component transmitted by each PLP is allocated such that the total number of cells of the physical layer frame matches the total number of cells of the plurality of PLPs, is received, and the physical layer frame is processed.

According to the first and second aspects of the present technology, when one frequency band is configured with a plurality of PLPs, band control of the PLPs can be performed.

Additionally, the effects described herein are not necessarily limited and may be any of the effects described in the present disclosure.

Figure 1 is a drawing showing an example configuration of a transmission system to which the present technology is applied.
Fig. 2 is a drawing showing an example configuration of the transmitter device of Fig. 1.
Figure 3 is a drawing showing an example of the configuration of the receiving device of Figure 1.
Figure 4 is a drawing explaining an outline of the band control of PLP.
Figure 5 is a diagram illustrating the structure of a physical layer frame.
Figure 6 is a diagram showing an example of parameters of a subframe.
Figure 7 is a diagram showing an example of parameters of PLP.
Figure 8 is a diagram showing the control unit of a segment.
Figure 9 is a drawing explaining the segment band change method and segment division method when a new change occurs.
Figure 10 is a diagram explaining data control of NRT content.
Figure 11 is a diagram showing a list of band control methods of the present technology.
Figure 12 is a drawing explaining band control when band control method 1 is adopted.
Figure 13 is a diagram showing the relationship between transmission data and physical layer frames.
Figure 14 is a drawing explaining band control when band control method 2 is adopted.
Figure 15 is a drawing explaining band control when band control method 2B is adopted.
Figure 16 is a drawing explaining band control when band control method 3 is adopted.
Figure 17 is a drawing explaining band control when band control method 3A is adopted.
Figure 18 is a drawing explaining band control when band control method 4 is adopted.
Figure 19 is a drawing explaining band control when band control method 4A is adopted.
Figure 20 is a drawing explaining band control when band control method 4B is adopted.
Figure 21 is a flowchart explaining the flow of data processing on the transmitting side.
Figure 22 is a flowchart explaining the detailed flow of scheduling processing.
Figure 23 is a flowchart explaining the flow of data processing on the receiving side.
Fig. 24 is a drawing showing another configuration example of a transmitter device.
Figure 25 is a diagram showing an example of a computer configuration.

Hereinafter, embodiments of the present technology will be described with reference to the drawings. In addition, the description will be performed in the following order.

1. System configuration

2. Overview of PLP band control using this technology

3. Specific examples of bandwidth control

4. Flow of processing executed on each device

5. Variants

6. Computer Configuration

<1. System configuration>

(Example of transmission system configuration)

Fig. 1 is a diagram illustrating the configuration of one embodiment of a transmission system to which the present technology is applied. In addition, a system means a logical combination of multiple devices.

In Fig. 1, a transmission system (1) is composed of a transmitting device (10) and a receiving device (20). In this transmission system (1), data transmission is performed in compliance with the standards of digital broadcasting that employs an IP transmission method such as ATSC3.0.

The transmitting device (10) transmits content through a transmission line (30). For example, the transmitting device (10) transmits a broadcast stream including video, audio, etc. (components thereof) and signaling, which constitute content such as a television program, as a digital broadcast signal through a transmission line (30).

The receiving device (20) receives and outputs content transmitted from the transmitting device (10) through the transmission line (30). For example, the receiving device (20) receives a digital broadcast signal from the transmitting device (10), acquires video or audio, etc. (components thereof) and signaling constituting the content from the broadcast stream, and reproduces video or audio of the content, such as a television program.

In addition, in the transmission system (1) of Fig. 1, only one receiving device (20) is illustrated for simplicity of explanation, but multiple receiving devices (20) can be installed, and the digital broadcast signal transmitted by the transmitting device (10) can be simultaneously received by multiple receiving devices (20) through the transmission line (30).

In addition, in the transmission system (1), the transmission line (30) may be, in addition to terrestrial broadcasting, satellite broadcasting using a broadcasting satellite (BS) or a communications satellite (CS), or cable broadcasting using a cable (CATV).

(Example of transmitter configuration)

Fig. 2 is a drawing showing an example of the configuration of the transmitting device (10) of Fig. 1.

In FIG. 2, the transmitting device (10) is composed of a scheduler (101), a first series processing unit including a data acquisition unit (102-1), an encoder (103-1 to 103-3), a multiplexer (104-1), and a PLP processing unit (105-1), a second series processing unit including a data acquisition unit (102-2), an encoder (103-4 to 103-5), an NRT processing unit (103-6), a multiplexer (104-2), and a PLP processing unit (105-2), a physical layer processing unit (106), and a transmitting unit (107).

In addition, in the transmitting device (10) of Fig. 2, one frequency band (for example, a 6 MHz frequency band corresponding to one channel (physical channel)) can be processed to be configured by a plurality of PLPs, but in order to simplify the explanation, a case will be described where processing is performed to be configured by two PLPs, PLP#1 (for example, a normal PLP) and PLP#2 (for example, a robust PLP). That is, in the transmitting device (10) of Fig. 2, processing regarding the normal PLP#1 is performed by the first series processing unit, and processing regarding the robust PLP#2 is performed by the second series processing unit. In addition, in ATSC3.0, up to 64 PLPs can be arranged in one frequency band.

The scheduler (101) performs processing related to control of encoding performed by the encoder (103-1) to the NRT processing unit (103-6) and processing related to bandwidth control of PLP performed by the PLP processing unit (105-1) and the PLP processing unit (105-2).

Additionally, physical layer information is input to the scheduler (101). This physical layer information includes the total number of cells indicating the number of cells in the entire physical layer frame (PHY Frame) and modulation parameters for each PLP.

Here, the total number of cells is a parameter that is determined uniquely when the structure of the physical layer frame (e.g., frame length, etc.) is determined. In addition, a cell is one set of encoded I/Q components in a constellation.

Specifically, the physical layer frame consists of a bootstrap (BS), a preamble, and a payload. The length of the bootstrap is specified as 2㎳ (=0.5㎳×4) in ATSC3.0. In addition, the length of the preamble and payload can be obtained by subtracting the length of the bootstrap (2㎳) from the length of the entire physical layer frame.

In addition, the preamble and payload are composed of data cells, cells of L1 signaling, pilot cells, and null cells. The number of these cells can be determined by modcod (e.g., modulation method, code length, code rate, etc.) determined for each PLP, and modulation parameters such as FFT size, guard interval length, pilot pattern, and number of carriers determined for each subframe.

By utilizing these relationships, the total number of cells can be obtained. In addition, the detailed structure of the subframe is described later with reference to FIGS. 5 to 7. In addition, the total number of cells of the physical layer information can be transmitted as information (L1B_L1_Detail_total_cells) included in the signaling of the physical layer.

In addition, the modulation parameters include parameters such as a modulation method for each PLP (e.g., PLP#1 and PLP#2). In addition, if the modulation parameters are changed, the receivable range of the digital broadcast signal transmitted from the transmitting device (10) changes, so once broadcasting is started, the modulation parameters are basically fixed.

The data acquisition unit (102-1) acquires data of components (e.g., video, audio, subtitles, etc.) that constitute content such as television programs, and supplies them to the encoder (103-1), encoder (103-2), and encoder (103-3).

In addition, in the description below, a component (data of) processed by an encoder (103-1) is referred to as component C1, a component (data of) processed by an encoder (103-2) is referred to as component C2, and a component (data of) processed by an encoder (103-3) is referred to as component C3.

The data acquisition unit (102-2) acquires data of components (e.g., video, audio, subtitles, etc.) that constitute content such as television programs, and supplies them to the encoder (103-4), encoder (103-5), and NRT processing unit (103-6).

In addition, in the description below, the component (data of) processed by the encoder (103-4) is referred to as component C4, the component (data of) processed by the encoder (103-5) is referred to as component C5, and the component (data of) processed by the NRT processing unit (103-6) is referred to as component C6 (NRT content).

Here, as the first series processing units, the encoder (103-1), the encoder (103-2), and the encoder (103-3), and as the second series processing units, the encoder (103-4), the encoder (103-5), and the NRT processing unit (103-6) supply code difficulty information indicating the difficulty of the code according to the component to be processed to the scheduler (101).

That is, for example, the encoder (103-1) supplies code difficulty information indicating the code difficulty of component C1, such as a moving image or an image close to a still image, to the scheduler (101). Similarly, in the encoder (103-2) to the NRT processing unit (103-6), code difficulty information regarding components C2 to C6 is supplied to the scheduler (101).

The scheduler (101) is supplied with code difficulty information from each of the encoder (103-1) to the NRT processing unit (103-6). The scheduler (101) determines the number of cells (the number of cells for each component) to be allocated to components C1 to C6 transmitted by each PLP (e.g., PLP#1 and PLP#2) based on, for example, the code difficulty information.

Here, the number of cells is determined by allocating a large number of cells (code amounts) to images with high code difficulty, such as images with a lot of movement, while allocating a small number of cells (code amounts) to images with low code difficulty, such as images close to still images. In addition, the modulation parameters are different for each PLP, such as normal PLP#1 and robust PLP#2, for example. By using these modulation parameters, the code amounts (hereinafter referred to as target code amounts) of components C1 to C6 processed by the encoder (103-1) to the NRT processing unit (103-6) can be calculated from the number of cells of each component.

The target code amount produced in this manner is supplied to the encoder (103-1) and the NRT processing unit (103-6), respectively.

The encoder (103-1) encodes the data of component C1 supplied from the data acquisition unit (102-1) according to a predetermined encoding method based on the target code amount supplied from the scheduler (101) and supplies the data to the multiplexer (104-1). However, the data of component C1 processed by the encoder (103-1) is processed in segment units according to the target code amount.

Here, a segment (hereinafter also referred to as a segment S) is a control unit determined by a segment length T and a bandwidth W. Within each segment S, a constant bit rate (CBR: Constant Bit rate) is applied, and the amount of code changes on a segment-by-segment basis. In addition, the detailed structure of the segment is described later with reference to FIGS. 8 and 9.

Likewise, in the encoder (103-2) and the encoder (103-3), each of the data of component C2 and component C3 supplied from the data acquisition unit (102-1) is encoded based on the target code amount supplied from the scheduler (101) and supplied to the multiplexer (104-1). However, the data of component C2 processed by the encoder (103-2) and the data of component C3 processed by the encoder (103-3) are processed in segment units according to the target code amount.

In addition, in the encoder (103-4) to the NRT processing unit (103-6), each of the data of components C4 to C6 supplied from the data acquisition unit (102-2) is encoded based on the target code amount supplied from the scheduler (101) and supplied to the multiplexer (104-2). However, the data of component C4 processed by the encoder (103-4), the data of component C5 processed by the encoder (103-5), and the data of component C6 processed by the NRT processing unit (103-6) are processed in segment units according to the target code amount.

That is, the scheduler (101) dynamically changes the amount of codes within the segment S by controlling at least one of the segment length T and the bandwidth W of each segment S as a segment-by-segment processing according to the target amount of codes performed by the encoder (103-1) to the NRT processing unit (103-6).

A multiplexer (104-1) multiplexes data of component C1 supplied from an encoder (103-1), data of component C2 supplied from an encoder (103-2), and data of component C3 supplied from an encoder (103-3), and supplies a multiplexed stream obtained thereby to a PLP processing unit (105-1).

A multiplexer (104-2) multiplexes data of component C4 supplied from an encoder (103-4), data of component C5 supplied from an encoder (103-5), and data of component C6 supplied from an NRT processing unit (103-6), and supplies the multiplexed stream obtained thereby to a PLP processing unit (105-2).

Additionally, the scheduler (101) calculates the number of cells of PLP#1 and the number of cells of PLP#2 based on the number of cells of components C1 to C6.

Here, the total number of cells included in the physical layer information represents the total number of cells in the physical layer frame, but the total number of cells in the physical layer frame (N _total ) is equal to the sum of the number of cells in each PLP, as shown in the following equation (1).

In addition, in equation (1), N _total on the left side represents the number of cells in the entire physical layer frame. In addition, N _i on the right side represents the number of cells in each PLP, and i represents the number of the PLP.

And, in the configuration of Fig. 2, since the number of cells (N _total ) of the entire physical layer frame becomes equal to the sum of the number of cells of PLP#1 and the number of cells of PLP#2, for example, by allocating the number of cells of the entire physical layer frame to PLP#1 and PLP#2 according to the number of cells of components C1 to C6, the number of cells of PLP#1 and the number of cells of PLP#2 are calculated.

Among the cell numbers for each PLP generated in this manner, the cell number of PLP#1 is supplied to the PLP processing unit (105-1), and the cell number of PLP#2 is supplied to the PLP processing unit (105-2).

The PLP processing unit (105-1) processes the multiplexed stream supplied from the multiplexer (104-1) based on the number of cells of PLP#1 supplied from the scheduler (101), thereby controlling the bandwidth of PLP#1. As a result, transmission data according to the number of cells of PLP#1 is supplied to the physical layer processing unit (106).

The PLP processing unit (105-2) processes the multiplexed stream supplied from the multiplexer (104-2) based on the number of cells of PLP#2 supplied from the scheduler (101), thereby controlling the bandwidth of PLP#2. As a result, transmission data according to the number of cells of PLP#2 is supplied to the physical layer processing unit (106).

The physical layer processing unit (106) generates a physical layer frame (PHY Frame) based on the transmission data according to the number of cells of PLP#1 supplied from the PLP processing unit (105-1) and the transmission data according to the number of cells of PLP#2 supplied from the PLP processing unit (105-2). However, the number of cells in the entire physical layer frame matches the sum of the number of cells of PLP#1 and the number of cells of PLP#2. In addition, the physical layer frame is composed of a bootstrap (BS: Bootstrap), a preamble, and a payload, and the transmission data of PLP#1 and PLP#2 are arranged in the payload.

The physical layer frame generated by the physical layer processing unit (106) is supplied to the transmitter unit (107).

The transmitter (107) performs an IFFT (Inverse Fast Fourier Transform) on the physical layer frame supplied from the physical layer processing unit (106), and performs a D/A conversion (Digital to Analog Conversion) on the resulting OFDM (Orthogonal Frequency Division Multiplexing) signal. Then, the transmitter (107) modulates the OFDM signal, which has been converted from a digital signal to an analog signal, into an RF (Radio Frequency) signal, and transmits it as a digital broadcasting signal in the IP transmission method through the antenna (121).

The transmitting device (10) is configured as described above. In addition, in Fig. 2, for the sake of explanation, the transmitting device is configured as a transmitting device (10), i.e., a single device, but it may be configured as a transmitting system including a plurality of devices having each function of the block in Fig. 2.

In addition, in the transmitter device (10) of Fig. 2, a configuration corresponding to two PLPs, PLP#1 and PLP#2, is shown, but in the case where one frequency band (for example, a frequency band of 6㎒) is configured with three or more PLPs, a series processing unit according to the number of PLPs may be installed.

(Example configuration of receiving device)

Fig. 3 is a drawing showing an example of the configuration of the receiving device (20) of Fig. 1.

In Fig. 3, the receiving device (20) is composed of a receiving unit (201), a demodulation processing unit (202), a demultiplexer (203), a decoder (204), and an output unit (205).

The receiving unit (201) receives a digital broadcasting signal in the IP transmission method transmitted from the transmitting device (10) through the transmission line (30) through the antenna (221), converts the RF signal into an IF (Intermediate Frequency) signal, and supplies the same to the demodulation processing unit (202).

The demodulation processing unit (202) performs demodulation processing (e.g., OFDM demodulation) on a signal supplied from the receiving unit (201). In addition, the demodulation processing unit (202) performs error correction processing on a demodulated signal obtained through the demodulation processing, and supplies a multiplexed stream obtained as a result of the processing to a demultiplexer (203).

The demultiplexer (203) separates the multiplexed stream supplied from the demodulation processing unit (202) into component (video, audio, subtitle) data and supplies it to the decoder (204).

The decoder (204) decodes component data supplied from the demultiplexer (203) according to a predetermined decoding method and supplies it to the output unit (205).

The output section (205) is configured with, for example, a display section or a speaker. The display section displays an image according to video data supplied from the decoder (204). In addition, the speaker outputs sound according to audio data supplied from the decoder (204). In addition, the output section (205) may output video or audio data supplied from the decoder (204) to an external device.

The receiving device (20) is configured as described above. In addition, the receiving device (20) may be a mobile receiver such as a mobile phone, a smart phone, or a tablet terminal, in addition to a fixed receiver such as a television set, a set-top box (STB), or a recorder. In addition, the receiving device (20) may be a vehicle-mounted device mounted on a vehicle.

<2. Overview of PLP band control using this technology>

(Overview of PLP's Bandwidth Control)

Fig. 4 is a drawing explaining an outline of the band control of PLP in the transmitter (10).

In Fig. 4, the direction from the top to the bottom in the drawing is the direction of time, and it is illustrated that the bandwidth of PLP#1 and PLP#2 arranged in a physical layer frame (PHY Frame) is changed by performing bandwidth control of the PLP.

In addition, in Fig. 4, the physical layer frame is composed of a bootstrap (BS), a preamble, and a payload, and the transmission data of PLP#1 and PLP#2 are arranged in the payload. In addition, the size of the physical layer frame is fixed, so the number of cells in the entire physical layer frame is constant, and therefore, by performing bandwidth control of the PLP, the total number of cells of PLP#1 and PLP#2 does not change, but the ratio of the number of cells of PLP#1 and the number of cells of PLP#2 changes. That is, in PLP#1 and PLP#2, the bit rate changes according to the ratio of the number of cells.

That is, at time t1, in the physical layer frame, the number of cells of PLP#1 and the number of cells of PLP#2 are almost the same. Then, from time t1 to time t2, in the physical layer frame, the number of cells of PLP#2 increases, while the number of cells of PLP#1 decreases by the amount of increase. Also, from time t2 to time t3, conversely, the number of cells of PLP#1 increases, while the number of cells of PLP#2 decreases by the amount of increase.

After that, similarly, from time t4 to time t7, in the physical layer frame, when the number of cells of PLP#1 increases, the number of cells of PLP#2 decreases accordingly, and when the number of cells of PLP#2 increases, the number of cells of PLP#1 decreases accordingly.

In this way, assuming that the total number of cells in the physical layer frame is constant, PLP bandwidth control is performed by changing the number of cells of PLP#1 and PLP#2.

Also, in reality, as illustrated in FIG. 5, the physical layer frame is composed of a bootstrap (BS), a preamble, and one or more subframes, and data of one or more PLPs (e.g., PLP#1 and PLP#2) are placed in these subframes.

Here, as parameters that can be changed for each subframe, there are parameters such as FFT size (L1D_fft_size), guard interval length (L1D_guard_interval), or pilot pattern (L1D_scattered_pilot_pattern), as shown in Fig. 6. In addition, as parameters that can be changed for each PLP, there are parameters such as code length (L1D_plp_fec_type), modulation method (L1D_plp_mod), or coding rate (L1D_plp_cod), as shown in Fig. 7.

(Structure of segments)

Figure 8 is a drawing showing the structure of segment S.

Segment S is a control unit determined by the segment length T and bandwidth W. Within this segment S, the bit rate is constant and the code amount changes for each segment.

Here, each segment S starts from a RAP (Random Access Point). The RAP indicates the position of a frame, such as an I frame in a GOP (Group of Pictures), from which a complete image can be obtained.

In addition, when a scene change occurs, an I frame is inserted, so there are two I frames with a large amount of generated codes in the segment S, and since only half the amount of generated codes can be allocated to each I frame when the bandwidth is fixed, the image quality deteriorates. However, a scene change occurs when there is no correlation between the focused frame and the previous frame that is temporally continuous with the focused frame.

Therefore, in the present technology, when a new change occurs, by processing segment S by a segment band change method or a segment division method, it is possible to suppress the deterioration of image quality caused by the insertion of an I frame when a new change occurs.

Specifically, as illustrated in A of Fig. 9, in processing of segment S by the segment bandwidth changing method, when a scene change occurs, the bandwidth W of segment S is expanded to bandwidth W', thereby (temporarily) increasing the bandwidth within segment S. In this case, even if an I frame or P frame is inserted, since the bandwidth within segment S is increased, it is possible to suppress deterioration of image quality when a scene change occurs. In addition, even if there is a change in the amount of codes that cannot be predicted in advance other than a scene change, the bandwidth can be increased or decreased in the same manner.

In addition, as illustrated in B of Fig. 9, in processing of segment S by the segment division method, when a new change occurs, the target segment S is terminated at that point and a new segment S is started. In this case, in the target segment S, even during processing for a GOP, processing for the GOP is forcibly terminated (terminated at the segment length T' (T' < T)), and processing for the new GOP is restarted in the new segment S. Then, in the new segment S, processing for the leading I frame, for example, is performed.

In this way, when a new change occurs, by terminating the target segment S even in the middle of a predetermined segment length and starting a new segment S (that is to say, by dividing the segment S), for example, there are no two I frames in the segment S, and it is possible to suppress deterioration of the image quality when a new change occurs. In addition, even in a case other than a new change, when an increase in the amount of codes that cannot be predicted in advance occurs, a new segment S can be started in the same manner.

As described above, in the present technology, processing is basically performed in segment units, but in a situation where normal segment unit processing cannot be performed (e.g., a situation where the bandwidth must be increased), such as when a new change occurs, segment S is exceptionally processed in accordance with a predetermined method, such as a segment bandwidth change method or a segment division method.

In addition, when employing a hierarchical encoding technique, there is an advantage in that decoding and synchronization processing become easier by making components of different layers the same segment length T.

(Data control using NRT content)

Figure 10 is a diagram explaining data control using NRT content.

However, the bandwidth of the physical layer (PHY) that complies with general broadcast standards is a fixed bit rate. To achieve this, the data encoding is controlled so that the code amount of the data of the components (video or audio) that constitute content such as television programs is optimized for the quality (mainly image quality) of each content within a range that does not exceed the fixed bit rate of the physical layer.

At this time, in the part that is insufficient for the fixed bit rate, a Null Packet is inserted and adjusted to the fixed bit rate. Also, in the physical layer, for example, the amount of codes generated is reduced by header compression technology or variable-length header technology, but in the case that is insufficient for the fixed bit rate, a Null Packet is inserted.

This appearance is illustrated in Fig. 10A. The waveform L of Fig. 10A represents the relationship between the amount of generated codes of digital broadcasting that conforms to general broadcasting standards on the vertical axis and the passage of time t on the horizontal axis, and the area of the range _Z0 below the waveform L becomes the sum of the amount of generated codes. That is, the amount of generated codes changes with the amount of generated codes Sx, which is a fixed bit rate of the physical layer, as the maximum value, as represented by the waveform L.

However, in the physical layer, since it is necessary to transmit at a fixed bit rate, for timings other than the timing when the occurrence code amount Sx, which is the maximum value of the waveform L, is insufficient in code amount, so a Null packet is inserted. That is, as shown in A of Fig. 10, for timings other than the occurrence code amount Sx, which is the maximum value, the range Z ₁ , which is equal to or greater than the waveform L and smaller than the maximum value of the occurrence code amount Sx, becomes the code amount of the Null packet, which is invalid data.

Meanwhile, in ATSC3.0, it is required to make effective use of a limited bandwidth, and it is desirable not to use null packets, which are invalid data, as they also cause a decrease in transmission efficiency. Therefore, transmission efficiency can be improved by transmitting data of non-real-time (NRT: Non Real Time) NRT content together with real-time (RT: Real Time) data such as component C.

That is, as illustrated in B of Fig. 10, in timings other than the maximum occurrence code amount Sx, the range Z ₁₂ in the range from the waveform L to the maximum value of the occurrence code amount Sx becomes the data code amount of the NRT content instead of the Null packet.

However, since there are cases where the data of the corresponding NRT content cannot be included in the code amount that becomes a Null packet, the range Z ₁₁ on the upper side of the range Z ₁₂ becomes the code amount of the reduced Null packet. In this way, the range Z ₀ and the range Z ₁₂ become valid transmission packets. As a result, since it becomes possible to use almost the entire range of the generated code amount Sx, which is the maximum value of the fixed bit rate, it becomes possible to improve the transmission efficiency.

In addition, in this technology, by noting that NRT content (component C6) is non-real-time data, the bandwidth of the data of the NRT content (component C6) is freely changed. That is, by controlling the bandwidth of the NRT content (component C6) according to the amount of codes generated from the data of other components (components C1 to C5), which are real-time data, the bandwidth of other components (components C1 to C5) is secured preferentially.

In this way, by using the bandwidth of NRT content (component C6) as, so to speak, a margin, bandwidth control in real time can be performed more easily. In addition, since NRT content (component C6) is non-real-time data, even if, for example, its bandwidth is temporarily set to 0 (zero), no problem occurs.

In addition, the inventor of the present application has already proposed a method of transmitting data of NRT content instead of a null packet in Japanese Patent Application No. 2014-127064.

<3. Specific examples of bandwidth control>

(List of band control methods)

Figure 11 is a diagram showing a list of band control methods of the present technology.

The bandwidth control method of the present technology is determined by a combination of the bandwidth W of segment S and segment length T of each component, the segment switching time, and the response when a new change occurs.

Here, as for the types of the band W of the segment S, there are two types: “constant” indicating that the width of the band W of the segment S of each component is constant, and “variable” indicating that the width of the band W of the segment S of each component changes from time to time.

In addition, as for the types of segment length T, there are two types: “constant” which indicates that the segment length T of the segment S of each component is constant, and “constant/variable” which indicates that the segment length T of the segment S of each component is constant or changes over time.

In addition, as for the types of segment transition times, there are two types: “simultaneous” which indicates that the transition times of segments S of each component are the same time, and “individual” which indicates that the transition times of segments S of each component are different. However, when the segment length T is “constant”, the segment transition time is “simultaneous”, while when the segment length T is “constant/variable”, the segment transition time is “individual”, and there is a correlation between the types of segment length T and the types of segment transition times.

In addition, as for the types of responses when a new change occurs, there are two types: “segment band change method” which indicates that the response when a new change occurs for each component is the segment band change method (A in Fig. 9), and “segment division method” which indicates that the response when a new change occurs for each component is the segment division method (B in Fig. 9). In addition, in the table of Fig. 11, “-” is described when the response when a new change occurs is not specifically determined.

In the table of Figure 11, eight band control methods are determined according to the combination of these types.

In bandwidth control method 1, control is performed so that the bandwidth W is “constant,” the segment length T is “constant,” and the segment switching time is “simultaneous.”

Bandwidth control method 2 and band control method 2B have in common that control is performed so that the band W is "constant", the segment length T is "constant/variable", and the segment switching time is "individual". On the other hand, band control method 2B differs in that control is performed so that the response when a new change occurs is in a "segment division method".

Bandwidth control method 3 and band control method 3A have in common that control is performed so that the band W is "variable", the segment length T is "constant", and the segment switching time is "simultaneous". On the other hand, band control method 3A differs in that control is performed so that the response when a new change occurs is in the "segment band change method".

Bandwidth control method 4, bandwidth control method 4A, and bandwidth control method 4B have in common that control is performed so that the band W is "variable", the segment length T is "constant/variable", and the segment switching time is "individual". On the other hand, in band control method 4A, control is performed using the "segment band change method" for response when a new change occurs, and in band control method 4B, control is performed using the "segment division method" for response when a new change occurs, which is different.

Below, specific examples of each band control method shown in the table of Fig. 11 are described in order.

(1) Band control method 1

Figure 12 is a drawing explaining band control when band control method 1 is adopted.

In Fig. 12, the horizontal axis represents time t, and the direction from the left to the right in the drawing is the direction of time. In addition, the vertical axis represents the number of cells (No of Cells), and it means that the number of cells increases as it goes toward the top in the drawing. That is, if the relationship between the time axis and the number of cells in Fig. 12 is expressed in physical layer frames, it can be expressed as in Fig. 13.

Returning to the description of Fig. 12, components C1 to C6 correspond to components C1 to C6 processed by the encoder (103-1) to the NRT processing unit (103-6) of Fig. 2.

That is, component C1 represents a component processed by the encoder (103-1) (Fig. 2), and as segment S of this component C1, segment S11, segment S12, segment S13, ..., segment S1t (t is an integer greater than or equal to 1) are processed in sequence.

Likewise, components C2 to C5 represent components processed by encoders (103-2) to (103-5) (Fig. 2). Then, as segments S of component C2, segments S21, ..., S2t (t is an integer greater than or equal to 1) are processed in sequence, and as segments S of component C3, segments S31, ..., S3t (t is an integer greater than or equal to 1) are processed in sequence. In addition, as segments S of component C4, segments S41, ..., S4t (t is an integer greater than or equal to 1) are processed in sequence, and as segments S of component C5, segments S51, ..., S5t (t is an integer greater than or equal to 1) are processed in sequence.

In addition, component C6 represents NRT content processed by the NRT processing unit (103-6) (Fig. 2), and as segment S of this component C6 (NRT content), segments S61, ..., S6t (t is an integer greater than or equal to 1) are processed in sequence.

In addition, in the following description, components C1 to C6 are referred to as components C when there is no need to specifically distinguish them. In addition, segments S11 to S1t, segments S21 to S2t, segments S31 to S3t, segments S41 to S4t, segments S51 to S5t, and segments S61 to S6t are referred to as segments S when there is no need to specifically distinguish them. In addition, the relationship between these is also the same in FIGS. 14 to 20 described below.

Here, in the bandwidth control method 1 of Fig. 12, control is performed by the scheduler (101) (Fig. 2) so that the bandwidth W and the segment length T of the segment S are "constant" and also so that the segment switching time is "simultaneous". That is, in the bandwidth control method 1, since the bandwidth W and the segment length T of each segment S are "constant", in the area of each segment S determined by the bandwidth W and the segment length T for each component C (an area of a different shape for each segment of each component in the drawing), the width in the vertical direction and the width in the horizontal direction are identical.

In addition, in bandwidth control method 1, since the segment switching time is "simultaneous", the switching time of segment S in each component C is repeated at regular intervals.

For example, focusing on each segment S of component C1, at time t1, segment S11 starting from time t0 is switched to segment S12, at time t2, segment S12 starting from time t1 is switched to segment S13, and at time t3, segment S13 starting from time t2 is switched to segment S14. In addition, at this time, the bandwidth of each segment S in component C1 is constant.

However, in Fig. 12, the period from time t0 to time t1, the period from time t1 to time t2, and the period from time t2 to time t3 are the same period. In addition, in Fig. 12, for the sake of explanation, the period from time t0 to time t3 is illustrated, but in the subsequent period as well, temporally continuous previous and subsequent segments in component C1 (e.g., segment S14 and segment S15) are sequentially switched at regular intervals.

Similarly, when looking at each segment S of component C2, at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals, the temporally consecutive previous and subsequent segments S (e.g., segment S21 and segment S22, segment S22 and segment S23, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C2 is constant.

Similarly, when looking at each segment S of component C3, at each time t of a constant period (e.g., time t1, time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S31 and segment S32, segment S32 and segment S33, etc.) are sequentially switched. Also, at this time, the bandwidth of each segment S in component C3 is constant.

And, each segment S in component C1 to component C3 processed by encoder (103-1) to encoder (103-3) is multiplexed by multiplexer (104-1), and the multiplexed stream obtained thereby is processed as PLP#1 by PLP processing unit (105-1).

In addition, when looking at each segment S of component C4, at each time t of a constant period (e.g., time t1 or time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S41 and segment S42, segment S42 and segment S43, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C4 is constant.

Similarly, when looking at each segment S of component C5, at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals, the temporally consecutive previous and subsequent segments S (e.g., segment S51 and segment S52, segment S52 and segment S53, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C5 is constant.

Similarly, when looking at each segment of component C6 (NRT content), at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals, temporally consecutive previous and subsequent segments S (e.g., segment S61 and segment S62, segment S62 and segment S63, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C6 is constant.

And, each segment S in component C4 to component C6 processed by the encoder (103-4) to NRT processing unit (103-6) is multiplexed by a multiplexer (104-2), and the multiplexed stream obtained thereby is processed as PLP#2 by the PLP processing unit (105-2).

In this way, in the bandwidth control method 1 of Fig. 12, the switching of temporally continuous segments S in each component C is performed simultaneously at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals.

Specifically, for example, at time t1, segments S11 and S12 of component C1, segments S21 and S22 of component C2, segments S31 and S32 of component C3, segments S41 and S42 of component C4, segments S51 and S52 of component C5, and segments S61 and S62 of component C6 are switched simultaneously.

Also, for example, at time t2, segments S12 and S13 of component C1, segments S22 and S23 of component C2, segments S32 and S33 of component C3, segments S42 and S43 of component C4, segments S52 and S53 of component C5, and segments S62 and S63 of component C6 are being switched simultaneously.

Above, the bandwidth control in the case of adopting bandwidth control method 1 was explained.

(2) Band control method 2

Figure 14 is a drawing explaining band control when band control method 2 is adopted.

In the bandwidth control method 2 of Fig. 14, control is performed by the scheduler (101) (Fig. 2) so that the bandwidth W is "constant", the segment length T is "constant/variable", and furthermore, the segment switching time is "individual". That is, in the bandwidth control method 2, the bandwidth W of each segment S is "constant", but the segment length T is "constant/variable", so that in the area of each segment S determined by the bandwidth W and the segment length T for each component C (an area of a different shape for each segment of each component in the drawing), the widths in the vertical direction are the same, but the widths in the horizontal direction are different.

In addition, in bandwidth control method 2, since the segment switching time is “individual,” the switching time of segment S in each component C is not a fixed period.

For example, if we focus on each segment S of component C1, at each time t (e.g., time t1, time t2, etc.) for each variable period, the temporally consecutive previous and subsequent segments S (e.g., segment S11 and segment S12, segment S12 and segment S13, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C1 is constant.

Similarly, when looking at each segment S of component C2, at each time t in a variable period (for example, a time different from time t1 or time t2), the temporally consecutive previous and subsequent segments S (for example, segment S21 and segment S22, segment S22 and segment S23, segment S23 and segment S24, etc.) are sequentially switched. Also, at this time, the bandwidth of each segment S in component C2 is constant.

Similarly, when looking at each segment S of component C3, at each time t in a variable period (for example, a time different from time t1 or time t2), the temporally consecutive previous and subsequent segments S (for example, segment S31 and segment S32, segment S32 and segment S33, segment S33 and segment S34, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C3 is constant.

And, each segment S in component C1 to component C3 processed by encoder (103-1) to encoder (103-3) is multiplexed by multiplexer (104-1), and the multiplexed stream obtained thereby is processed as PLP#1 by PLP processing unit (105-1).

In addition, when looking at each segment S of component C4, at each time t (for example, a time different from time t1 or time t2) for each variable period, the temporally continuous previous and subsequent segments S (for example, segment S41 and segment S42, segment S42 and segment S43, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C4 is constant.

Similarly, when looking at each segment S of component C5, at each time t (for example, a time different from time t1 or time t2) for each variable period, the temporally consecutive previous and subsequent segments S (for example, segment S51 and segment S52, segment S52 and segment S53, etc.) are sequentially switched. Also, at this time, the bandwidth of each segment S in component C5 is constant.

Similarly, when looking at each segment of component C6 (NRT content), at each time t (for example, a time different from time t1 or time t2) for each variable period, temporally consecutive previous and subsequent segments S (for example, segment S61 and segment S62, segment S62 and segment S63, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C6 is constant.

And, each segment S in component C4 to component C6 processed by the encoder (103-4) to NRT processing unit (103-6) is multiplexed by a multiplexer (104-2), and the multiplexed stream obtained thereby is processed as PLP#2 by the PLP processing unit (105-2).

In this way, in the band control method 2 of Fig. 14, the switching of temporally consecutive segments S in each component C is not performed simultaneously, but is performed at each time t (e.g., time t1, time t2, etc.) for each variable period.

Specifically, for example, at time t1, segments S11 and S12 of component C1 are switched, but at this time, in components C2 to C6, segment S is not switched. In addition, for example, at time t2, segments S12 and S13 of component C1 are switched, but at this time, in components C2 to C6, segment S is not switched.

Also, since it is repeated, I will not explain for all, but also for components C2 to C6, when switching its own segment S, at that timing, switching of other segments S in other components C is not performed.

Above, the bandwidth control in the case of adopting bandwidth control method 2 was explained.

(3) Band control method 2B

Figure 15 is a drawing explaining band control when band control method 2B is adopted.

In the bandwidth control method 2B of Fig. 15, the scheduler (101) (Fig. 2) controls the bandwidth W to be "constant", the segment length T to be "constant/variable", and furthermore, the segment switching time to be "individual", which is common to the bandwidth control method 2 (Fig. 14). On the other hand, the bandwidth control method 2B differs from the bandwidth control method 2 (Fig. 14) in that processing using the segment division method is performed when a new change occurs, and the following description focuses on this point.

That is, in the bandwidth control method 2B, the bandwidth W of each segment S is "constant", but the segment length T is "constant/variable", so in the area of each segment S determined by the bandwidth W and the segment length T for each component C (an area of a different shape for each segment of each component in the drawing), the widths in the vertical direction are the same, but the widths in the horizontal direction are different. In addition, in the bandwidth control method 2B, the segment switching time is "individual", so the switching time of the segment S in each component C is not a constant period.

Here, focusing on each segment S of component C1, if a scene change occurs at time t2 during processing of segment S12, then, depending on the segment division method, at that point in time, segment S12 is forcibly terminated even in the middle of a predetermined segment length, and processing of a new segment S13 is started. As a result, for example, there are no two I frames in segment S, and deterioration of image quality when a scene change occurs can be suppressed.

Above, the band control in the case of adopting the band control method 2B was explained.

(4) Band control method 3

Figure 16 is a drawing explaining band control when band control method 3 is adopted.

In the bandwidth control method 3 of Fig. 16, control is performed by the scheduler (101) (Fig. 2) so that the bandwidth W is "variable", the segment length T is "constant", and furthermore, the segment switching time is "simultaneous". That is, in the bandwidth control method 3, the segment length T of each segment S is "constant", but the bandwidth W is "variable", so that in the area of each segment S determined by the bandwidth W and the segment length T for each component C (an area of a different shape for each segment of each component in the drawing), the widths in the horizontal direction are the same, but the widths in the vertical direction are different.

In addition, in bandwidth control method 3, since the segment switching time is "simultaneous", the switching time of segment S in each component C is repeated at regular intervals.

For example, if we focus on each segment S of component C1, at each time t at regular intervals (e.g., time t1, time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S11 and segment S12, segment S12 and segment S13, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C1 is variable and changes for each segment S.

Similarly, when focusing on each segment S of component C2, at each time t of a certain period (e.g., time t1, time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S21 and segment S22, segment S22 and segment S23, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C2 is variable and changes for each segment S.

Similarly, when looking at each segment S of component C3, at each time t in a given period (e.g., time t1, time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S31 and segment S32, segment S32 and segment S33, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C3 is variable and changes for each segment S.

And, each segment S in component C1 to component C3 processed by encoder (103-1) to encoder (103-3) is multiplexed by multiplexer (104-1), and the multiplexed stream obtained thereby is processed as PLP#1 by PLP processing unit (105-1).

In addition, when looking at each segment S of component C4, at each time t of a certain period (e.g., time t1, time t2, etc.), the temporally consecutive previous and subsequent segments S (e.g., segment S41 and segment S42, segment S42 and segment S43, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C4 is variable and changes for each segment S.

Similarly, when looking at each segment S of component C5, at each time point t (e.g., time t1, time t2, etc.) at regular intervals, the temporally consecutive previous and subsequent segments S (e.g., segment S51 and segment S52, segment S52 and segment S53, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C5 is variable and changes for each segment S.

Similarly, when looking at each segment of component C6 (NRT content), at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals, temporally consecutive previous and subsequent segments S (e.g., segment S61 and segment S62, segment S62 and segment S63, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C6 is variable and changes for each segment S.

And, each segment S in component C4 to component C6 processed by the encoder (103-4) to NRT processing unit (103-6) is multiplexed by a multiplexer (104-2), and the multiplexed stream obtained thereby is processed as PLP#2 by the PLP processing unit (105-2).

In this way, in the bandwidth control method 3 of Fig. 16, the switching of temporally continuous segments S in each component C is performed simultaneously at each time point t (e.g., time point t1, time point t2, etc.) at regular intervals.

Specifically, for example, at time t1, segments S11 and S12 of component C1, segments S21 and S22 of component C2, segments S31 and S32 of component C3, segments S41 and S42 of component C4, segments S51 and S52 of component C5, and segments S61 and S62 of component C6 are switched simultaneously.

Also, for example, at time t2, segments S12 and S13 of component C1, segments S22 and S23 of component C2, segments S32 and S33 of component C3, segments S42 and S43 of component C4, segments S52 and S53 of component C5, and segments S62 and S63 of component C6 are being switched simultaneously.

However, since the band of each segment S in components C1 to C6 is variable, it changes for each segment S in each component C.

Above, the bandwidth control in the case of adopting bandwidth control method 3 was explained.

(5) Band control method 3A

Figure 17 is a drawing explaining band control when band control method 3A is adopted.

In the band control method 3A of Fig. 17, the scheduler (101) (Fig. 2) controls the band W to be "variable", the segment length T to be "constant", and the segment switching time to be "simultaneous", which is common to the band control method 3 (Fig. 16). On the other hand, the band control method 3A differs from the band control method 3 (Fig. 16) in that processing using the segment band changing method is performed when a new change occurs, and the following description focuses on this point.

That is, in the bandwidth control method 3A, the segment length T of each segment S is "constant", but the bandwidth W is "variable", so in the area of each segment S determined by the bandwidth W and the segment length T for each component C (an area of a different shape for each segment of each component in the drawing), the widths in the horizontal direction are the same, but the widths in the vertical direction are different. In addition, in the bandwidth control method 3A, the segment switching times are "simultaneous", so the switching times of the segment S in each component C are a constant period.

Here, focusing on each segment S of component C1, when a scene change occurs at time t2, according to the segment bandwidth change method, at that point in time, by expanding the bandwidth W of segment S12, the bandwidth within segment S12 is (temporarily) increased. In this case, even if, for example, an I frame or a P frame is inserted, since the bandwidth within segment S is increased, it is possible to suppress deterioration of the image quality when a scene change occurs.

In addition, in this example, at time t2, the bandwidths of segments S22, S32, S42, and S52 are shifted upward in conjunction with the expansion of the bandwidth W of segment S12, but since the bandwidth of the NRT content (component C6) is used as, so to speak, a margin, it is possible to respond to the scene change in segment S12 without reducing the bandwidth of those segments S.

Above, the band control in the case of adopting the band control method 3A was explained.

(6) Band control method 4

Figure 18 is a drawing explaining band control when band control method 4 is adopted.

In the bandwidth control method 4 of Fig. 18, control is performed by the scheduler (101) (Fig. 2) so that the bandwidth W is "variable", the segment length T is "constant/variable", and furthermore, the segment switching time is "individual". That is, in the bandwidth control method 4, the bandwidth W of each segment S is "variable" and the segment length T is "constant/variable", so that for each component C, in the area of each segment S determined by the bandwidth W and the segment length T (an area of a different shape for each segment of each component in the drawing), the vertical width and the horizontal width do not match.

In addition, in band control method 4, since the segment switching time is “individual,” the switching time of segment S in each component C is not a fixed period.

For example, if we focus on each segment S of component C1, at each time t (e.g., time t1, time t2, etc.) in each variable period, the temporally consecutive previous and subsequent segments S (e.g., segment S11 and segment S12, segment S12 and segment S13, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C1 is variable and changes for each segment S.

Similarly, when looking at each segment S of component C2, at each time t (for example, a time different from time t1 or time t2) for each variable period, temporally consecutive previous and subsequent segments S (for example, segment S21 and segment S22, segment S22 and segment S23, segment S23 and segment S24, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C2 is variable and changes for each segment S.

Similarly, when looking at each segment S of component C3, at each time t in a variable period (for example, a time different from time t1 or time t2), the temporally continuous previous and subsequent segments S (for example, segment S31 and segment S32, segment S32 and segment S33, segment S33 and segment S34, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C3 is variable and changes for each segment S.

And, each segment S in component C1 to component C3 processed by encoder (103-1) to encoder (103-3) is multiplexed by multiplexer (104-1), and the multiplexed stream obtained thereby is processed as PLP#1 by PLP processing unit (105-1).

In addition, when looking at each segment S of component C4, at each time t (for example, a time different from time t1 or time t2) for each variable period, the temporally continuous previous and subsequent segments S (for example, segment S41 and segment S42, segment S42 and segment S43, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C4 is variable and changes for each segment S.

Similarly, when looking at each segment S of component C5, at each time t (for example, a time different from time t1 or time t2) for each variable period, the temporally consecutive previous and subsequent segments S (for example, segment S51 and segment S52, segment S52 and segment S53, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C5 is variable and changes for each segment S.

Similarly, when looking at each segment of component C6 (NRT content), at each time t (for example, a time different from time t1 or time t2) for each variable period, temporally consecutive previous and subsequent segments S (for example, segment S61 and segment S62, segment S62 and segment S63, etc.) are sequentially switched. In addition, at this time, the bandwidth of each segment S in component C6 is variable and changes for each segment S.

And, each segment S in component C4 to component C6 processed by the encoder (103-4) to NRT processing unit (103-6) is multiplexed by a multiplexer (104-2), and the multiplexed stream obtained thereby is processed as PLP#2 by the PLP processing unit (105-2).

In this way, in the bandwidth control method 4 of Fig. 18, the switching of temporally consecutive segments S in each component C is not performed simultaneously, but is performed at each time t (e.g., time t1, time t2, etc.) for each variable period.

Specifically, for example, at time t1, segments S11 and S12 of component C1 are switched, but at this time, in components C2 to C6, switching of segment S is not performed. In addition, for example, at time t2, segments S12 and S13 of component C1 are switched, but at this time, in components C2 to C6, switching of segment S is not performed.

Also, although it is repeated and not explained for all, in components C2 to C6 as well, when switching its own segment S, at that timing, switching of other segments S in other components C is not performed.

Above, the band control in the case of adopting the band control method 4 was explained.

(7) Band control method 4A

Figure 19 is a drawing explaining band control when band control method 4A is adopted.

In the band control method 4A of Fig. 19, the scheduler (101) (Fig. 2) controls the band W to be "variable", the segment length T to be "constant/variable", and furthermore, the segment switching time to be "individual", which is common to the band control method 4 (Fig. 18). On the other hand, the band control method 4A differs from the band control method 4 (Fig. 18) in that processing using the segment band changing method is performed when a new change occurs, and the following description focuses on this point.

That is, in the bandwidth control method 4A, since the bandwidth W of each segment S is "variable" and the segment length T is "constant/variable", for each component C, in the area of each segment S determined by the bandwidth W and the segment length T (an area of a different shape for each segment of each component in the drawing), the vertical width and the horizontal width do not match. In addition, in the bandwidth control method 4A, since the segment switching time is "individual", the switching time of the segment S in each component C is not a constant period.

Here, focusing on each segment S of component C1, when a scene change occurs at time t2, according to the segment bandwidth change method, at that point in time, by expanding the bandwidth W of segment S12, the bandwidth within segment S12 is (temporarily) increased. In this case, even if, for example, an I frame or a P frame is inserted, since the bandwidth within segment S is increased, it is possible to suppress deterioration of the image quality when a scene change occurs.

In addition, in this example, at time t2, the bands of segments S23, S32, S42, S43, and S53 are shifted upward in conjunction with the expansion of the band W of segment S12, but since the band of the NRT content (component C6) is used as, so to speak, a margin, it is possible to respond to the scene change in segment S12 without reducing the band of those segments S.

Above, the band control in the case of adopting the band control method 4A was explained.

(8) Band control method 4B

Figure 20 is a drawing explaining band control when band control method 4B is adopted.

In the band control method 4B of Fig. 20, the scheduler (101) (Fig. 2) controls the band W to be "variable", the segment length T to be "constant/variable", and furthermore, the segment switching time to be "individual", which is common to the band control method 4 (Fig. 18). On the other hand, the band control method 4B differs from the band control method 4 (Fig. 18) in that processing is performed using the segment division method when a new change occurs, and the following description focuses on this point.

That is, in the bandwidth control method 4B, since the bandwidth W of each segment S is "variable" and the segment length T is "constant/variable", for each component C, in the area of each segment S determined by the bandwidth W and the segment length T (an area of a different shape for each segment of each component in the drawing), the vertical width and the horizontal width do not match. In addition, in the bandwidth control method 4B, since the segment switching time is "individual", the switching time of the segment S in each component C is not a constant period.

Here, focusing on each segment S of component C1, if a scene change occurs at time t2 during processing of segment S12, then, depending on the segment division method, at that point in time, segment S12 is forcibly terminated even in the middle of a predetermined segment length, and processing of a new segment S13 is started. As a result, for example, there are no two I frames in segment S, and deterioration of image quality when a scene change occurs can be suppressed.

Above, the band control in the case of adopting the band control method 4B was explained.

<4. Flow of processing executed on each device>

Next, with reference to the flowcharts of FIGS. 21 to 23, the flow of processing executed in the transmitting device (10) and receiving device (20) constituting the transmission system (1) of FIG. 1 will be described.

(Flow of data processing on the transmitter side)

First, referring to the flow chart of Fig. 21, the flow of data processing on the transmission side executed by the transmission device (10) of Fig. 1 will be described.

In step S101, the scheduler (101) performs scheduling processing. In this scheduling processing, processing related to control of encoding performed by the encoder (103-1) to the NRT processing unit (103-6) and processing related to band control of PLP performed by the PLP processing unit (105-1) and the PLP processing unit (105-2) are performed. In addition, details of the scheduling processing are described later with reference to the flowchart of Fig. 22.

In step S102, the encoder (103-1) to the NRT processing unit (103-6) perform component processing. In this component processing, data of components C1 to C6 are processed (encoded) in segment units according to the target code amount produced in the processing of step S101.

Additionally, data of components C1 to C3 are multiplexed by a multiplexer (104-1), and data of components C4 to C6 are multiplexed by a multiplexer (104-2).

In step S103, the PLP processing unit (105-1) and the PLP processing unit (105-2) perform PLP processing. In this PLP processing, the PLP processing unit (105-1) performs bandwidth control of PLP#1 based on the number of cells of PLP#1 calculated in the processing of step S101. In addition, the PLP processing unit (105-2) performs bandwidth control of PLP#2 based on the number of cells of PLP#2 calculated in the processing of step S101.

In step S104, the physical layer processing unit (106) performs physical layer processing. In this physical layer processing, a physical layer frame in which a PLP according to the processing band control of step S103 is placed in the payload is generated.

In step S105, the transmitter (107) performs transmission processing of a digital broadcast signal. In this transmission processing, the physical layer frame generated in the processing of step S104 is processed and transmitted as a digital broadcast signal in the IP transmission method.

When the processing of step S105 is completed, the data processing on the transmission side of Fig. 21 is completed.

Above, the flow of data processing on the transmitting side has been explained.

(Flow of scheduling processing)

Next, with reference to the flowchart of Fig. 22, the detailed processing flow of the scheduling processing corresponding to the processing of step S101 of Fig. 21 will be described.

In step S121, the scheduler (101) acquires physical layer information input thereto. This physical layer information includes a total cell count indicating the number of cells in the entire physical layer frame and modulation parameters for each PLP.

In step S122, the scheduler (101) acquires code difficulty information supplied from each of the encoder (103-1) to the NRT processing unit (103-6).

In step S123, the scheduler (101) determines the number of cells for each component.

Here, for example, the number of cells of each component can be determined based on the code difficulty information acquired in the processing of step S122. In addition, by using the modulation parameter for each PLP acquired in the processing of step S121, the target code amount can be obtained from the number of cells of each component. The target code amount obtained in this way is supplied to the encoder (103-1) to the NRT processing unit (103-6), respectively.

In addition, for example, based on the number of cells of each component determined in the processing of step S123, the number of cells of PLP#1 and the number of cells of PLP#2 can be calculated. Then, the number of cells of PLP#1 is supplied to the PLP processing unit (105-1), and the number of cells of PLP#2 is supplied to the PLP processing unit (105-2).

When the processing of step S123 is completed, the processing returns to the processing of step S101 of Fig. 21, and the processing thereafter is executed.

Above, the flow of scheduling processing is explained.

(Flow of data processing on the receiving side)

Next, with reference to the flow chart of Fig. 23, the flow of data processing on the receiving side executed by the receiving device (20) of Fig. 1 will be described.

In step S201, the receiving unit (201) performs reception processing of a digital broadcast signal. In this reception processing, a digital broadcast signal of an IP transmission method transmitted from a transmitting device (10) through a transmission path (30) is received.

In step S202, the demodulation processing unit (202) performs demodulation processing on the signal obtained in the processing of step S201. In this demodulation processing, OFDM demodulation and error correction processing, etc. are performed. In addition, the multiplexed stream obtained in this demodulation processing is separated into component data by a demultiplexer (203).

In step S203, the decoder (204) decodes the component data obtained in the processing of step S202 according to a predetermined decoding method.

In step S204, the output unit (205) displays an image according to the video data obtained in the processing of step S203. In addition, the output unit (205) outputs a sound according to the audio data obtained in the processing of step S203.

When the processing of step S204 is completed, the receiving side data processing of Fig. 23 is completed.

Above, the flow of data processing on the receiving side has been explained.

<5. Variant Example>

(Other configuration examples of transmitters)

However, in ATSC3.0, channel bonding, which combines and uses multiple channels (frequency bands), is adopted, and an example of the configuration of a transmitting device (10) corresponding to this channel bonding is illustrated in Fig. 24. In the transmitting device (10) of Fig. 24, multiple channels (frequency bands) are combined and used by the physical layer processing unit (106).

In addition, in channel bonding, a frequency hopping method may be adopted. Here, frequency hopping is a technology for changing the frequency band used at regular intervals for purposes such as countermeasures against fading.

In addition, in the above description, in order to simplify the explanation, the explanation was centered on components as data that require securing bandwidth, but it is necessary to secure bandwidth for real-time data (e.g., service information (SI), etc.) other than non-real-time data such as NRT content. Bandwidth control can also be performed for such real-time data in the same manner as for the above-described components.

In addition, although the above description describes ATSC (particularly, ATSC3.0), which is a method adopted in the United States and other countries as a standard for digital broadcasting, this technology may be applied to ISDB (Integrated Services Digital Broadcasting), which is a method adopted in Japan and other countries, or DVB (Digital Video Broadcasting), which is a method adopted in European countries and other countries. Furthermore, as digital broadcasting, in addition to terrestrial broadcasting, it can be applied to satellite broadcasting such as BS (Broadcasting Satellite) or CS (Communications Satellite), and wired broadcasting such as cable television (CATV).

In addition, the present technology can also be applied to a predetermined standard (standard other than digital broadcasting standard) that assumes the use of a transmission line other than a broadcasting network, that is, a communication line (communication network) such as the Internet or a telephone network, as a transmission line. In that case, a communication line such as the Internet or a telephone network is used as a transmission line (30), and the transmitting device (10) can be a server installed on the Internet. Then, by making the receiving device (20) have a communication function, the transmitting device (10) performs processing in response to a request from the receiving device (20).

<6. Computer Configuration>

The above-described series of processes can be executed by hardware or by software. When the series of processes are executed by software, the program constituting the software is installed in the computer. Fig. 25 is a diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program.

In a computer (900), a CPU (Central Processing Unit) (901), a ROM (Read Only Memory) (902), and a RAM (Random Access Memory) (903) are connected to each other by a bus (904). An input/output interface (905) is further connected to the bus (904). An input unit (906), an output unit (907), a recording unit (908), a communication unit (909), and a drive (910) are connected to the input/output interface (905).

The input unit (906) includes a keyboard, a mouse, a microphone, etc. The output unit (907) includes a display, a speaker, etc. The recording unit (908) includes a hard disk or a nonvolatile memory, etc. The communication unit (909) includes a network interface, etc. The drive (910) drives a removable media (911) such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

In a computer (900) configured as described above, the CPU (901) loads and executes a program recorded in a ROM (902) or a storage unit (908) into the RAM (903) via an input/output interface (905) and a bus (904), thereby performing the above-described series of processes.

The program executed by the computer (900) [CPU (901)] can be provided by being recorded on removable media (911), such as package media, for example. In addition, the program can be provided through a wired or wireless transmission medium, such as a local area network, the Internet, or digital satellite broadcasting.

In the computer (900), the program can be installed in the recording unit (908) through the input/output interface (905) by mounting the removable media (911) in the drive (910). In addition, the program can be received by the communication unit (909) through a wired or wireless transmission medium and installed in the recording unit (908). In addition, the program can be installed in advance in the ROM (902) or the recording unit (908).

Here, in this specification, the processing that the computer performs according to the program does not necessarily have to be performed in time series according to the order described in the flow chart. That is, the processing that the computer performs according to the program also includes processing that is executed in parallel or individually (e.g., parallel processing or processing by objects). In addition, the program may be processed by one computer (processor) or may be processed in a distributed manner by multiple computers.

In addition, the embodiments of the present technology are not limited to the embodiments described above, and various changes are possible without departing from the gist of the present technology.

In addition, the present technology can take the following configuration.

(1)

A processing unit that determines the number of cells of a component transmitted by each PLP so that the total number of cells of a physical layer frame including multiple PLPs (Physical Layer Pipes) matches the total number of cells of the multiple PLPs;

A transmitting device having a transmitting unit for transmitting a broadcast stream including the above physical layer frame.

(2)

The above component is a transmitter described in (1) that processes segment units determined by segment length and bandwidth.

(3)

The transmitting device described in (2) above, wherein the processing unit dynamically changes the code amount of the segment by variably controlling at least one of the segment length and the bandwidth for each segment.

(4)

The above-mentioned plurality of PLPs are a transmitting device as described in (1) in which each PLP has a different modulation parameter.

(5)

The above processing unit is a transmitting device described in (2) that increases or decreases the bandwidth within the target segment when a change occurs in the amount of code generated by the above component.

(6)

The above processing unit is a transmitting device described in (2) that terminates the target segment and starts a new segment when an increase in the amount of codes generated by the above component occurs.

(7)

The above processing unit is a transmitting device described in (2) that controls the bandwidth of a segment of the non-real-time component according to the amount of code generation of the real-time component when the component includes a non-real-time component.

(8)

A transmitting device according to any one of (1) to (7), wherein the total number of cells of the physical layer frame is a parameter that is unilaterally determined when the structure of the physical layer frame is determined.

(9)

In a data processing method of a transmitting device,

The above transmitting device,

The number of cells of a component transmitted by each PLP is determined so that the total number of cells of a physical layer frame including multiple PLPs is equal to the sum of the number of cells of the multiple PLPs,

A data processing method comprising a step of transmitting a broadcast stream including the above physical layer frame.

(10)

A physical layer frame including a plurality of PLPs, wherein a receiver receives a broadcast stream including the physical layer frame to which the number of cells of components transmitted by each PLP is allocated such that the total number of cells of the physical layer frame matches the total number of cells of the plurality of PLPs;

A receiving device having a processing unit for processing the above physical layer frame.

(11)

The above-mentioned plurality of PLPs are a receiving device as described in (10) in which each PLP has a different modulation parameter.

(12)

In a data processing method of a receiving device,

The above receiving device,

A physical layer frame including a plurality of PLPs, wherein a broadcast stream including the physical layer frame is received in which the number of cells of the components transmitted by each PLP is allocated such that the total number of cells of the physical layer frame matches the total number of cells of the plurality of PLPs,

A data processing method comprising a step of processing the above physical layer frame.

1: Transmission system
10: Transmitter
20 : Receiver
30 : Transmission route
101 : Scheduler
102-1, 102-2: Data Acquisition Section
103-1 to 103-5: Encoder
103-6: NRT Processing Unit
104-1, 104-2 : Multiplexer
105-1, 105-2: PLP Processing Unit
106: Physical layer processing unit
107 : Transmitter
201 : Receiver
202: Reproduction Processing Unit
203 : Demultiplexer
204 : Decoder
205 : Output section
900 : Computer
901 : CPU

Claims (16)

A processing unit configured to place a plurality of components including video and/or audio data constituting the content of a broadcast program to be transmitted in each of at least one PLP (Physical Layer Pipe) within a physical layer frame;
A transmitter configured to transmit a broadcast stream including the above physical layer frame,
The above components are processed in segment units determined by segment length and bandwidth.
The above processing unit is configured to dynamically change the code amount of the segment by variably controlling at least one of the segment length and the bandwidth for each segment,
Each segment is initiated by a transmitting device with a random access point. In the first paragraph,
At least one of the above PLPs is a transmitting device having different modulation parameters for each PLP. In the first paragraph,
The above processing unit is a transmitting device configured to increase or decrease a bandwidth within a target segment when a change in the amount of code generation of the above component occurs. In the first paragraph,
The above processing unit is a transmitting device configured to terminate a target segment and initiate a new segment when an increase in the amount of codes generated by the above component occurs. In the first paragraph,
The above processing unit is a transmitting device configured to control the bandwidth of a segment of the non-real-time component according to the amount of code generation of the real-time component when the component includes a non-real-time component. In the first paragraph,
A transmitting device in which the total number of cells in the above physical layer frame is a parameter that is unilaterally determined when the structure of the above physical layer frame is determined. In a data processing method of a transmitting device,
The above transmitting device,
A step of arranging a plurality of components to be transmitted in each of at least one PLP within a physical layer frame, wherein the plurality of components include video and/or audio data constituting the content of a broadcast program; and
comprising a step of transmitting a broadcast stream including the above physical layer frame,
The above data processing method
A step for processing the above components in segment units determined by segment length and bandwidth; and
For each of the above segments, the method further comprises a step of dynamically changing the code amount of the segment by variably controlling at least one of the segment length and the bandwidth,
A data processing method in which each segment is initiated by a random access point. A receiving unit configured to receive a broadcast stream including a physical layer frame having at least one PLP, wherein a plurality of components including video and/or audio data constituting the content of a broadcast program are arranged;
A processing unit configured to process the above physical layer frame is provided,
The above components are processed in segment units determined by segment length and bandwidth.
For each of the above segments, at least one of the segment length and the bandwidth is variably controlled, so that the code amount of the segment is dynamically changed.
Each segment is initiated by a receiving device with a random access point. In Article 8,
A receiving device wherein at least one of the above PLPs has different modulation parameters for each PLP. In Article 8,
A receiving device in which a band within a target segment of a component is changed when a change in the occurrence code amount of the component occurs. In Article 8,
A receiving device in which, when an increase in the occurrence code amount of a component occurs, the target segment is terminated and a new segment is initiated. In Article 8,
A receiving device in which, when including a non-real-time component as a component, the bandwidth of a segment of the non-real-time component is changed according to the amount of code generation of the real-time component. delete In Article 8,
The above random access point is a receiving device containing an I-frame in a Group of Pictures (GOP). In Article 8,
A receiving device in which segments of two or more components are initiated or terminated simultaneously. In a data processing method of a receiving device,
The above receiving device,
A step for receiving a broadcast stream including a physical layer frame having at least one PLP, wherein a plurality of components including video and/or audio data constituting the content of a broadcast program are arranged; and
Including a step for processing the above physical layer frame,
The above components are processed in segment units determined by segment length and bandwidth.
For each of the above segments, at least one of the segment length and the bandwidth is variably controlled, so that the code amount of the segment is dynamically changed.
A data processing method in which each segment is initiated by a random access point.

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